A graph is subhamiltonian if it is a subgraph of a planar Hamiltonian graph.
A plane graph \(G^{\prime }\) 
is said to be obtained by stellating a face \(F\)  of the plane
graph \(G\)  if \(G^{\prime }\) 
is obtained from \(G\)  by adding a new vertex \(F^*\) 
in the interior
of \(F\)  and continuous curves joining it to each vertex in the boundary of the
face in such a way that the curves intersect \(G\)  only at their endpoints and
the curves are disjoint except for \(F^*\) .
See, e.g., [1]}.
